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Lithium concentration in serum/plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of lithium, a medication, in your blood. It helps doctors monitor your treatment for conditions like bipolar disorder or certain types of depression.

Quick summary

["Lithium levels help ensure your medication stays within safe ranges."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
3720-0
Short code
Lithium SerPl Ql
Synonyms
Lithium SerPl Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.6
Ref high
1.2
Critical range
— – 1.6 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test if you’re taking lithium to manage mood disorders, seizures, or other conditions. Regular checks help prevent side effects like toxicity or insufficient dosing.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re on lithium, your doctor may adjust timing to avoid testing during peak or trough levels.

What the Results Mean

Results are compared to a general reference range for healthy adults. Too-high or too-low levels can indicate problems with your medication or kidney function.

Common Causes of Abnormal Results

High levels may be due to overmedication, dehydration, or kidney issues. Low levels could mean your body isn’t absorbing enough lithium or you’re missing doses.

Reference range

Therapeutic: 0.6-1.2 mmol/LN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lithium Level

Frequently asked questions

Why do I need this test regularly?
Regular testing helps your doctor adjust your dose safely. It also catches early signs of lithium building up in your body (toxicity) or working too little.
What if my results are outside the normal range?
Your doctor will review your results with you and may change your medication, dose, or timing. They’ll also check your kidney function if needed.
Can I eat or drink before this test?
You can eat normally, but avoid caffeine or alcohol before testing. If you’re on lithium, ask your doctor about timing to avoid interfering with the test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy